Headset for reproducing quadraphonically recorded information

ABSTRACT

The present invention relates to a headset for reproducing information recorded quadraphonically by a four-channel technique using four separate microphones, said headset possessing respective acoustic transmitters for the front sound and the rear sound, in each headset earpiece, the acoustic transmitters being covered by a supporting wall containing a sound opening of special design, and the earpiece rim being provided with a cushioned ring of such depth that when the headset is in position on the head, the ear occupies its natural position away from the head, and divides the earpiece interior, defined by the cushioned ring and the supporting wall, into a front and rear zone, without isolating said two zones from each other.

United States Patent [1 1 Goeckel Dec. 16, 1975 HEADSET FOR REPRODUCING QUADRAPHONICALLY RECORDED INFORMATION Helmut Goeckel, Liebenau-Weser, Germany [73] Assignee: Neckermann Versand KGaA,

Frankfurt am Main, Germany [22] Filed: June 11, 1974 [21] Appl. No.: 478,378

[75] Inventor:

[30] Foreign Application Priority Data June 12, 1973 Germany 2329851 [52] US. Cl. 179/1 GQ; 179/182 R [51] Int. Cl. H04R l/10; H04R 5/00 [58] Field of Search 179/1 GQ, 156 R, 182 R [56] References Cited UNITED STATES PATENTS 3,794,779 2/1974 Greuzerd l79/156 R 3,796,840 3/1974 Ohta 179/156 R Primary ExaminerWilliam C. Cooper Attorney, Agent, or Firml-laseltine, Lake & Waters [57] ABSTRACT The present invention relates to a headset for reproducing information recorded quadraphonically by a four-channel technique using four separate microphones, said headset possessing respective acoustic transmitters for the front sound and the rear sound, in each headset earpiece, the acoustic transmitters being covered by a supporting wall containing a sound opening of special design, and the earpiece rim being provided with a cushioned ring of such depth that when the headset is in position on the head, the ear occupies its natural position away from the head, and divides the earpiece interior, defined by the cushioned ring and the supporting wall, into a front and rear zone, without isolating said two zones from each other.

12 Claims, 9 Drawing Figures U.S. Patent Dec. 16,1975 Shet10f2 3,927,262

FIG. 1a

U.S. Patent Dec.16,1975 Sheet20f2 3,927,262

each case fed via a third and a fourth channel to two loudspeakers set up behind the listener. In this fashion, both a right/left orientation as well as a front/rear orientation is achieved.

Whereas when using loudspeaker reproduction the described spatial orientation can be simulated by setting up the four loudspeakers, one each in front of the listener at right and left and one each behind him at right and left, in headset reproduction arrangements have to be made and measures taken to make the same kind of spatial orientation possible for the human ear.

In the following, we will confine ourselves to a discussion of one human ear and one headset earpiece in order to explain how the front/rear sound impression is created. However, it will be self-evident that the other ear and the other headset earpiece, produces the right- /left orientation using similar information, and therefore completes the quadraphonic sound impression.

Orientation on the front right/left and rear right/left loudspeakers, ensured by visual experience, becomes unreliable in headset reception because here the visual aid provided by the various positions of the loudspeakers, is lacking. Although, in the case of a headset, righthand/lefthand hearing is unambiguous because of the distribution of the righthand and lefthand information to the respective earpieces of the headset, it is difficult nevertheless, to effect a distinction between front and rear and to estimate the distance of the sources from the recording microphone, ie the spatial structure of the recording location. It is not sufficient simply to incorporate into each earpiece a front and a rear acoustic transmitter and inject quadraphonic information on the assumption that the listener will hear this in the quadraphonic form. The reason for the inability to effect directional orientation, is concerned with the interruption of the transport flow and of the chronological sequence of the transport function, this destroying the simultaneity of arrival of the different instantaneous values of the four pieces of information, at the auditory canal.

The object of the invention is to provide a headset for the reproduction of genuine quadraphonically recorded information and also stero-ambiphonic and other quadrupolar presentations, which allows the listener to reliably and realistically determine the direction of origin and distance of the original presentation as well as the spatial extent, of an orchestra for example, and causes the different instantaneous values responsible for the spatial presentation to become effective simultaneously and in correct sequence in order to simulate the spatial effect.

The invention is based upon the following new realisations: The local positioning of a microphone at a recording location must faithfully reproduce the microphone set-ups in the original location through an analagous, congruent positioning of the corresponding acoustic transmitters around the auditory canal to serve as analogues of the positionsof the recording microphones. All the four pieces of quadrophonic information supply different instantaneous values serving as spatial parameters and range parameters, which must arrive at the auditory canal in the same timebased directional relationship, with which they are produced at the time of recording.

Any correct reproduction of a quadraphonic presentation is thus in effect a fresh production or second production of the original microphone recording. The four acoustic transmitters must therefore in respect of the auditory canal, generate the same spatial structural features which were offered to the microphones by the original.

If for example a piece of information containing forward sound, although correctly reproduced by the correct forward acoustic transmitter, reaches the auditory canal later than the simultaneous instantaneous value of the information carrying the rear sound and emanating from an appropriate rear acoustic transmitter at the same side, then the listeners perception centre is disturbed because the rear signal arriving first is interpreted as a front signal and a false spatial impression is created.

The headset, in accordance with the invention, must satisfy the following conditions:

1. The information arriving from the front and already containing front space features of the original, must arrive simultaneously with or slightly earlier than the information coming from the rear; however, it must not lag to such an extent that the same or simultaneously recorded different instantaneous values can no longer be detected as belonging together;

2. Information arriving from the front, must be conveyed directly and in bunched fashion, to the front side of the auricle and directed by the shortest possible path to the auditory canal;

3. The information arriving'from the rear must be rendered more diffuse, of faded tone colour as it were, i.e. without brilliance, force and clarity, and should arrive at the auditory canal as a simultaneous or very slightly lagging instantaneous value;

4. The internal acoustics of the headset earpieces must be such as to ensure that the source-inherent delay differences between the arrivals of the front and rear acoustic fronts, are applied without any modification in relation to the source original, to the diaphragm of the ear, since otherwise the ear will register incorrect orientations; The ear, in other words, is enclosed in the comparatively tiny chamber of the headset earpiece and is screened from the normal impressions and experiences; the ear must correctly receive the event sequences of the original performance without at the same time perceiving the distance of the acoustic sources in the interior of the earpiece. The experience programmed into the centre of the perception, will otherwise be disturbed by the addition of different dimensions and the spatial impression will be destroyed.

In addition to spatial orientation, the information also makes it possible to estimate the distance or in other words range to the original sound source. The acoustic information is a cohesive, propagating mixture of tones and sounds made up of direct and indirect information (formants timbres and volumes pp) but also including information about the distance of a source from the recording element (ear or microphone). The sounds in this mixture have a relationship to one another (envelope) which is determined by the distance of the sources and is the relationship in which they arrive at the microphones. If this sound mixture occurs at a different distance from the microphone or ear, then the same mixture will exhibit a different component structure. Both pieces of information thus, for example, are carrying the same concert, but are projected by the ear to a different auditory range.

Sound mixtures of this kind experience a loss of high frequencies on their way to the ear. This also is recorded by the ear as a measurement of range.

Spatial, directional and range parameters are: acoustic directions, tone colours, time differences, densities, phases, sequences, envelope curve differences and combinations of all these.

The present invention resolves the problem of the reproduction of the spatial information inherent in the original, by the following measures:

1. Each acoustic transmitter is arranged in a mounting designed as a pressure chamber, above its acoustic exit orifice.

2. The acoustic exit orifice for the forward sounds opens into the front zone of the earpiece interior in front of the auricle.

3. The rear sound exit orifice opens into the interior of the earpiece behind the auricle.

4. The front sound orifice is about smaller than the rear sound orifice.

5. The front sound orifice has an acoustic guide component, preferably in the form of a so-called scoop, open towards the front side of the auricle and exhibiting a flat reflection face inclined at about 60 which directs the front sound with force, brilliance and clarity onto the opening of the auditory canal.

6. The rear acoustic transmitter reproduces the character of the rear sound in different ways, by weaker or totally absent velocity transformation or/and by diffuse introduction into the rearward part of the earpiece zone behind the auricle.

These measures serve to ensure correct reproduction of the quadraphonic information and of the spatial and range parameters which it contains, without destroying its correct, differing instantaneous relationship as a consequence of false intermediate transport phenomena from the acoustic transmitter to the auditory canal.

Through different degrees of velocity transformation, for about the same interval between front and rear sound orifices in the interior of the earpiece and with simultaneous reproduction of the associated instantaneous values, it is reliably ensured that the front sound information arrives first so that the detour on the part of the rear sound, around the auricle, this rear sound experiencing a lesser velocity transformation, and the bunched and sharply reflected higher-amplitude front sound information, reliably avoid information reversal, without at the same time causing a piece of information to be spatially fragmented as it were because of the simultaneous mode of radiation of the instantaneous values. The simultaneity relates to the arrival of the four different instantaneous values at the ear, and it is this which is the critical factor.

Because of the greater velocity transformation taking place in the front sound, the introduction of the front information into the ear as the first information. whilst retaining simultaneity between the instantaneous val- 4 ues of the information, is ensured in accordance with the invention.

The supporting wall defining the interior surface of the earpiece cavity is lined (with the exception of the interior of the scoop) with a thin sound-absorbing layer in order to prevent any false reflection.

The improvement in contrast by selective minimal attenuation of the higher frequencies in a piece of information using reflection in order to more clearly distinguish range differences, is enhanced and given greater impact by reversing the position of the rear acoustic transmitter in relation to that of the front acoustic transmitter. This should not be confused with the Lauridsen effect which, by the reverse injection of a delayed signal picked off from one channel, into the other channel (and possibly into the originating channel as well) achieves a pseudo-stereophonic effect. In accordance with the present invention, an effect already present in the envelope curve of a piece of information, is simply made more easily distinguishable and given greater impact, by the use of two different measures, in fact by the creation of a steeper attenuation gradient towards the higher frequencies and by greater emphasis of this gradient in order to more clearly indicate the range.

Other details of the information will be apparent from the ensuing description of the examples illustrated in the drawings.

FIG. 1 is a cross-section through a first embodiment of a headset earpiece in accordance with the invention, with two acoustic transmitters and an indication of the position of the ear within the cavity defined by the cushioned ring;

FIG. 1a is a fragmentary view of the interior of the earpiece of FIG. 1, showing two acoustic transmitters and the acoustic exit orifices, concealed beneath the transmitters, the outer end wall of the earpiece having been removed;

FIG. 2 is a cross-section through a second embodiment of a headset earpiece in accordance with the invention, with obliquely disposed front acoustic transmitter and horizontally disposed rear acoustic transmitter;

FIG. 2a is a fragmentary view of the interior of the headset earpiece of FIG. 2, complete with the rear acoustic transmitter and the associated arcuate pressure chamber with the acoustic exit orifice;

FIG. 2b is a partial cross-section through the pressure chamber of the rear acoustic transmitter of FIG. 2a, complete with acoustic exit orifices;

FIG. 3 is a cross-section of a third embodiment of a headset earpiece in accordance with the invention, with a rear acoustic transmitter radiating towards the outer wall of the earpiece housing;

FIG. 3a is a view of the interior of the headset earpiece of FIG. 3, with the two acoustic transmitters, the acoustic exit orifice of the rear acoustic transmitter which operates into the interior of the earpiece housing, being visible at the righthand edge of the earpiece;

FIG. 4 is a cross-section through a fourth embodiment of a headset earpiece in accordance with the invention in which the acoustic exit orifice of the front acoustic transmitter is a short central section of tube and in which the mounting for the rear acoustic transmitter is not in fact a pressure chamber but consists of a series of spacers.

FIG. 4a is a view of the interior of the headset earpiece of FIG. 4, with the two acoustic transmitters, the outer wall of the earpiece having been removed.

FIG. 1 is a cross-section through a first embodiment of a headset earpiece marked in toto by l, the outer wall 2 of which is attached to the section 3 of the housing by its supporting wall 4, in some suitable manner or other. On the supporting wall 4, mountings 5 and 6 are formed which are inserted in sound-damping fashion into the front acoustic transmitter 7 and the rear acoustic transmitter 8. The diaphragms of the two acoustic transmitters are at certain intervals from the supporting wall 4, creating in respect of the lefthand front acoustic transmitter 7, a pressure chamber 9, and in respect of the righthand rear acoustic transmitter 8, a pressure chamber 10. These pressure chambers, in a manner known per se, through their orifices 11 and 16 create a velocity transformation in the sound. Centrally beneath the front acoustic transmitter 7, in the supporting wall 4, an acoustic exit orifice 1 1 and, beneath this, a scoop 12 open towards the auricle and formed on or otherwise attached to the supporting wall 4, are provided, said scoop exhibiting an acoustic reflector plate 13 flush with the front edge of the acoustic orifice and disposed at about 60 to the supporting wall 4. Scoop 12 and reflector plate 13 direct the front sound exiting from the acoustic exitorifice l1, and accelerate it by the shortest path, creating brilliance, force and clarity, and with the highest possible accuracy, to the opening 14 of the auditory canal and to the front side of the auricle 15. In this way, the form and structure of the envelope curve of the information are, in accordance with the invention, rendered richer in contrast in order to better discern the range of the sources from the recording microphone, this since reflections are responsible for partial attenuation of the high frequencies and this is perceived as an apparent increase in the distance of the source and therefore intensifies the range contrasts. Beneath the rear acoustic transmitter 8, the supporting wall 4 exhibits an acoustic exit orifice 16. In contrast to the acoustic exit orifice 11 of the front acoustic transmitter 7, this has no acoustic guide scoop and no reflector plate but directs the rear sound in diffuse fashion into the zone between the rear 17 of the auricle l5 and the cushioned ring 18 attached to the section 3 of the housing of the headset earpiece l. The acoustic exit orifice 16 of the rear acoustic transmitter 8 and its pressure chamber 10, is somewhat larger than that 11 of the front acoustic transmitter 7. Consequently, the velocity transformation effected by the front acoustic transmitter is somewhat greater than that produced by the rear acoustic transmitter so that if the different instantaneous values are simultaneous and if the acoustic transmitters have about the same intervals from the entrance to the auditory canal it is reliably ensured that the front acoustic information arrives range situations pertaining there, are ensured. The

cushioned ring 18 has a depth such that with the headset in position, the ear has the natural free attitude which it normally adopts, away from the head. The

' acoustic transmitters 7, 8, are pressed firmly to the mountings 5, 6 by a soft pad 19 of foam material.

FIG. 1a illustrates a fragmentary view of the interior of the earpiece with the front acoustic transmitter 7, its

mounting 5 and the rear acoustic transmitter 8 with its mounting 6, the outside wall 2 of the earpiece 1 having been removed. Beneath the front acoustic transmitter 7 and concealed by it in fact, there is the acoustic exit orifice 11, formed in the supporting wall 4 and shown in broken line, which orifice takes the form of a narrow rectangle. The acoustic exit orifice 16 beneath the rear acoustic transmitter 8, in the supporting wall, and shown in broken line fashion, has a slightly curved form, matching the cushioned ring, and in accordance with the invention is somewhat larger than the acoustic exit orifice 11 associated with the front acoustic transmitter 7.

FIG. 2 illustrates a second emboidment of a headset earpiece in accordance with the invention. It is distinguished from the first embodiment by the fact that the front acoustic transmitter 7 with its mounting 5 which here again is a pressure chamber, is obliquely inserted into the supporting wall 4 in such fashion that the sound which it produces is directed onto the opening 14 of the auditory canal and onto the front side of the auricle 15. Before doing so, however, the front sound has to pass through baffle-like strips 28 producing a double reflection (2 X arranged at an angle of about 45 to the direction of the sound and slightly overlapping one another. The rear acoustic transmitter 8, with its mounting 6 acting as a pressure chamber 10, is arranged in precisely the same way as the rear acoustic transmitter of the first embodiment shown in FIGS. l and 1a. At the left of the acoustic exit orifice 16 a low acoustic guide 21 is formed on the supporting wall 4, the guide extending into the space between the rear 17 of the auricle and the cushioned ring 18. This guide is intendedto direct the rear sound unambiguously, over a longer path, onto the rear 17 of the auricle.

FIG. 2a illustrates a fragmentary view of the interior of the headset earpiece of FIG. 2, with the rear acoustic transmitter 8, the supporting wall 2 having been removed and the cover 24 of the perforated chambers 23 having been lifted away. Its acoustic exit orifice consists here of a series of arcuately disposed holes 22 whose sum area is greater, in accordance with the invention, than that of the acoustic orifice 1 l of the front acoustic transmitter 7. These render the rear sound more diffuse so that its tone colour is more washed out, i.e. without force, brilliance and clarity. The shape of the chamber 23 and the associated pressure chamber 6, matches the arcuate disposition of the holes 22 and therefore approximates to the form of a kidney. FIG. 2b illustrates a cross section through the chamber 23 and the holes 22 in the supporting wall 4.

FIG. 3 illustrates a cross-section through a third embodiment of a headset earpiece in accordance with the invention. The shape of the mounting 5 or pressure chamber, and its arrangement, are the same as in the first embodiment. The other distinction resides in the fact that the mountings 5 and 24 for the front and rear acoustic transmitters 7, 8 are side by side and the rear acoustic transmitter 8 is centrally disposed, radiating towards the outer wall 2 into the cavity of the earpiece 1, between outer wall and supporting wall. The mounting 24, in this embodiment thus does not constitute a pressure chamber. The rear sound, over all, covers a longer path before leaving the acoustic exit orifice 16. This makes the rear sound more diffuse in nature.

FIG. 3a illustrates a view of the interior of the headset earpiece of FIG. 3, with the two acoustic transmitters 7 and 8, and the acoustic exit orifice l6.

FIG. 4 illustrates a cross-section through a fourth embodiment of a headset earpiece in accordance with the invention. In this case, the acoustic exit orifice for the front acoustic transmitter 7 is a short central piece of tube 26 and the mounting 5 acting as a pressure chamber. is connected in sound-damping fashion through an acoustic guide 27, to the input orifice of the central tube section 26. On its passage from the diaphragm of the front acoustic transmitter 7 to the tube section 26 via the acoustic guide 27, the sound experiences reflection at the flat plate 28, through an angle of 45. The mounting 29 of the rear acoustic transmitter 8, in this embodiment does not operate as a pressure chamber because it consists for example of a series of spacer feet 29 which are arranged equidistantly from one another in a circle and carry the rear acoustic transmitter 8. The spacer feet 29 are covered wholly or partly by a ring or strip 30 of porous soft foamed material. To the left of the acoustic exit orifice 16 for the rear acoustic transmitter 8, as in the embodiment of FIG. 2 there is an acoustic guide 21 formed on the supporting wall 4 in order to direct the rear sound onto the rear 17 of the auricle 15.

FIG. 4a illustrates a view of the interior of the headset earpiece 1 of FIG. 4, with the internal acoustic transmitter 7 and the acoustic guide 27 linking it and its mounting with the entry orifice of the short tube section 26 in sound-damping fashion. The rear acoustic transmitter 8 has been removed in order to show the spacer feet 29 and the surrounding ring or strip 30 of soft foamed material. 16 indicates the acoustic exit orifice for the rear acoustic transmitter 8 which, as FIG. 4a shows, has an elliptical shape.

I claim:

1. A headset for accurately reproducing quadraphonically recorded information, said headset including headset earpieces, acoustic transmitters for respectively the front sound and the rear sound being located in each said headset earpiece, a supporting wall having a sound opening of predetermined configuration, said wall covering said transmitters, and the earpiece including a rim, a cushioned ring being located on said rim and having a depth such that when the headset is in position on the head of a wearer, the ear occupies its unchanged natural position on the head, characterized in that the supporting wall includes two acoustic exit orifices spaced apart in predetermined relationship, but equidistant from the auditory canal opening of the ear, said orifices being of dissimilar sizes, the front orifice being associated with the front acoustic transmitter whilst the slightly larger orifice is associated with the rear acoustic transmitter; a mounting being provided in each of the two acoustic transmitters so as to act as a pressure chamber, on the supporting wall proximate the acoustic exit orifice for the front sound there being formed an acoustic guide for directing this sound onto the auditory canal of the ear; and the acoustic exit orifice of the rear acoustic transmitter being arranged at a point on the supporting wall so that the rear sound is directed into the zone between the cushioned ring and the rear of the auricle.

2. A headset as claimed in claim 1, characterized in that the acoustic guide is a scoop having a flat reflective face therein inclined at about 60 and adjoining the front edge of the acoustic exit orifice.

3. A headset as claimed in claim 1, characterized in that the acoustic guide is a short centrally arranged tube section; an acoustic guide connecting the entry 8 orifice to the pressure chamber in the mounting for the front acoustic transmitter so as to form a sound-damping barrier, and which includes a flat reflective face inclined at 45.

4. A headset as claimed in claim 1, characterized in that the acoustic exit orifice for front and rear sound components respectively, in each case has the form of a narrow rectangle.

5. A headset as claimed in claim 4, characterized in that the acoustic exit orifice for the rear sound consists of at least one arcuate slot which communicate with the pressure chamber through the enlarged sides of the pressure chamber, and have a combined area greater than the area of the front sound orifice.

6. A headset as claimed in claim 1, characterized in that the front acoustic transmitter with its mounting is disposed obliquely in the supporting wall, the mounting including flat strips forming lines of baffles at either side thereof, and strips being arranged at an angle of about 45 to the direction taken by the sound and, overlapping one another'slightly, directing the front sound onto the auditory canal of the ear.

7. A headset as claimed in claim 6, characterized in that the mounting of the rear acoustic transmitter is a pressure chamber and is of kidney-shaped form, the acoustic exit orifice in the supporting wall comprising a series of arcuately disposed holes, the sum of whose areas is greater than the area of the opening of the front acoustic transmitter.

8. A headset as claimed in claim 7, characterized in that a low acoustic guide is formed on the supporting wall which directs the rear sound towards the rear of the auricle and lengthens the acoustic trajectory.

9. A headset for accurately reproducing quadraphonically recorded information, including an earpiece, acoustic transmitter for the respectively front sound and one for the rear sound in each headset earpiece, the acoustic transmitters being covered by a supporting wall having acoustic exit orifices; a cushioning ring mounted on the rim of the earpiece of such a depth that the ear, when the headset is in place, is in its natural unchanged position on the head, characterized in that the acoustic transmitter for the front sound is arranged in a mounting forming a pressure chamber,

whilst the rear acoustic transmitter connected with a mounting so as to extend towards the external wall into the interior of the headset earpiece between said supporting wall and said external wall and in that the sound passes into the region between cushioned ring and the rear of the auricle through at least one acoustic exit orifice.

10. A headset as claimed in claim 9, characterized in that the pressure chamber mounting extends into an acoustic guide and is insulated relative thereto, the

interior of said guide communicating with a central tube section for the acoustic exit orifice and including a flat reflective face inclined at 45.

11. A headset as claimed in claim 9, characterized in that the mounting of the rear acoustic transmitter includes a series of circularly disposed spacer feet which are at least partly covered by a ring member of porous soft foamed material.

12. A headset as claimed in claim 9, characterized in that the interior of the earpiece, with the exception of the interior of the scoop on the supporting wall, is lined with a thin sound-absorbing layer. 

1. A headset for accurately reproducing quadraphonically recorded information, said headset including headset earpieces, acoustic transmitters for respectively the front sound and the rear sound being located in each said headset earpiece, a supporting wall having a sound opening of predetermined configuration, said wall covering said transmitters, and the earpiece including a rim, a cushioned ring being located on said rim and having a depth such that when the headset is in position on the head of a wearer, the ear occupies its unchanged natural position on the head, characterized in that the supporting wall includes two acoustic exit orifices spaced apart in predetermined relationship, but equidistant from the auditory canal opening of the ear, said orifices being of dissimilar sizes, the front orifice being associated with the front acoustic transmitter whilst the slightly larger orifice is associated with the rear acoustic transmitter; a mounting being provided in each of the two acoustic transmitters so as to act as a pressure chamber, on the supporting wall proximate the acoustic exit orifice for the front sound there being formed an acoustic guide for directing this sound onto the auditory canal of the ear; and the acoustic exit orifice of the rear acoustic transmitter being arranged at a point on the supporting wall so that the rear sound is directed into the zone between the cushioned ring and the rear of the auricle.
 2. A headset as claimed in claim 1, characterized in that the acoustic guide is a scoop having a flat reflective face therein inclined at about 60* and adjoining the front edge of the acoustic exit orifice.
 3. A headset as claimed in claim 1, characterized in that the acoustic guide is a short centrally arranged tube section; an acoustic guide connecting the entry orifice to the pressure chamber in the mounting for the front acoustic transmitter so as to form a sound-damping barrier, and which includes a flat reflective face inclined at 45*.
 4. A headset as claimed in claim 1, characterized in that the acoustic exit orifice for front and rear sound components respectively, in each case has the form of a narrow rectangle.
 5. A headset as claimed in claim 4, characterized in that the acoustic exit orifice for the rear sound consists of at least one arcuate slot which communicate with the pressure chamber through the enlarged sides of the pressure chamber, and have a combined area greater than the area of the front sound orifice.
 6. A headset as claimed in claim 1, characterized in that the front acoustic transmitter with its mounting is disposed obliquely in the supporting wall, the mounting including flat strips forming lines of baffles at either side thereof, and strips being arranged at an angle of about 45* to the direction taken by the sound and, overlapping one another slightly, directing the front sound onto the auditory canal of the ear.
 7. A headset as claimed in claim 6, characterized in that the mounting of the rear acoustic transmitter is a pressure chamber and is of kidney-shaped form, the acoustic exit orifice in the supporting wall comprising a series of arcuately disposed holes, the sum of whose areas is greater than the area of the opening of the front acoustic transmitter.
 8. A headset as claimed in claim 7, characterized in that a low acoustic guide is formed on the supporting wall which directs the rear sound towards the rear of the auricle and lengthens the acoustic trajectory.
 9. A headset for accurately reproducing quadraphonically recorded information, including an earpiece, acoustic transmitter for the respectively front sound and one for the rear sound in each headset earpiece, the acoustic transmitters being covered by a supporting wall having acoustic exit orifices; a cushioning ring mounted on the rim of the earpiece of such a depth that the ear, when the headset is in plAce, is in its natural unchanged position on the head, characterized in that the acoustic transmitter for the front sound is arranged in a mounting forming a pressure chamber, whilst the rear acoustic transmitter connected with a mounting so as to extend towards the external wall into the interior of the headset earpiece between said supporting wall and said external wall and in that the sound passes into the region between cushioned ring and the rear of the auricle through at least one acoustic exit orifice.
 10. A headset as claimed in claim 9, characterized in that the pressure chamber mounting extends into an acoustic guide and is insulated relative thereto, the interior of said guide communicating with a central tube section for the acoustic exit orifice and including a flat reflective face inclined at 45*.
 11. A headset as claimed in claim 9, characterized in that the mounting of the rear acoustic transmitter includes a series of circularly disposed spacer feet which are at least partly covered by a ring member of porous soft foamed material.
 12. A headset as claimed in claim 9, characterized in that the interior of the earpiece, with the exception of the interior of the scoop on the supporting wall, is lined with a thin sound-absorbing layer. 